A section of text which forms the start and/or destination of a
hypertext link is called an "anchor" and is defined by the
<a href="http://www.hal.com">HaL Computer Systems</a>
The most common attributes of the anchor tag are:
Optional - Level 0. If the
href attribute is present, the
anchor is sensitive text: the start of a link. If the reader
selects this text, (s)he moves to another document whose
network address is defined by the value of the
The format of the network address is specified in the URI
specification for print readers. With the
href attribute, the
href="#identifier" can refer to another anchor in the
same document. If the anchor is in another document,
the attribute may be a relative name (relative to the
document's address or the specified base address).
Optional - Level 0. If present, the attribute
the anchor to be the destination of a link. The value of the
attribute is an identifier for the anchor.
Identifiers are arbitrary strings but must be unique within the HTML document. Another document can then make a reference explicitly to this anchor by putting the identifier after the address, separated by a hash sign.
Optional - Level 1. The
title element is informational only.
If present the
title attribute should provide the title of the
document whose address is given by the
This is useful for at least two reason:
The browser software may chose to display the title of the document prior to retrieving it, for example as a margin note or on a small box while the mouse is over the anchor, or during document fetch.
Some documents -- mainly those which are not marked up text, such as graphics, plain text and also Gopher menus, do not come with a title themselves, and so putting a title in the link is the only way to give them a title. Obviously it leads to duplication of data, and so it is dangerous to assume that the title attribute of the link is a valid and unique title for the destination document.
Proposed - Level 1. An attribute
rel may give the
relationship (s) described by the hypertext link.
Proposed - Level 1. The
rev attribute is the same as
the semantics of the link type are in the reverse
Optional - Level 1. If present, the
urn attribute specifies a
uniform resource number (URN) for the document.
URNs allow a document to be recognized if duplicate
copies are found. This prevents a client implementation
from picking up a copy of something it already has.
The format of URNs is under discussion (1993) by various working groups of the Internet Engineering Task Force.
Optional - Level 1. The
methods attributes of anchors and
links provide information about the functions which the
user may perform on an object. These are more
accurately given by the HTTP protocol when it is used,
but it may, for similar reasons as for the
title attribute, be
useful to include the information in advance in the link.
For example, the browser may chose a different
rendering as a function of the methods allowed (for
example something which is searchable may get a
The value of the
methods attribute is a comma separated
list of HTTP methods supported by the object for public
Although all attributes are optional, either
necessary for the anchor to be useful. Example:
See <a href="http://www.hal.com/">HaL</a>'s information for more details.
<a name=indecent>Indecent</a> dress is defined as dress which the community finds offensive.
The restaurant may refuse service to anyone who is <a href="#indecent">indecently</a> dressed.
See also: link.